Also: you wanted to cancel jobs. thats easier to do. Use the method
-cupsCancelJob(destination, jobID)
destination is printer
jobid is an integer for the printjob
you can get both using:
currentNewJobCount = cupsGetJobs( &jobs, JOBS_FROM_ANY_DEST, JOBS_FROM_ANY_USER, ONLY_PROCESSING_JOBS);
where I defined statics const ints to make it more readable: the values of the arguments are 0's and 1's. See documentation for the specific values for your needs.
the destination printers and ids can be extracted from the array of jobs you created prior:
cups_job_t *jobs;
extract values as follows:
currentWindowDestination = jobs[i].dest;
currentWindowJobID = jobs[i].id;